Dim lights are a sign that the voltage is too low to the bulbs. This can be from a bad alternator, bad wiring or an issue with the headlight relay ( if equipped ).
Best to have a shop that is good with electrical diagnosis look at this to perform an electrical diagnosis of the headlight system.
They should check it out for .5 - 1.0 hours of diagnosis time, here are some in your area to call if you need one: http://repairpal.com/directory?address=90007&car_brand_names=Kia